This invention is generally directed to toner compositions, and more specifically, the present invention relates to developer compositions with toner compositions comprised of low melt resin particles. In one embodiment, the present invention relates to an encapsulated toner generated when a toner comprised of resin particles, colorants, such as known pigment particles, and optional additives, such as known charge control components, is subjected to halogenation, especially chlorination. An encapsulated toner comprised of a major amount of resin particles, which are usually low melting as illustrated herein, of the present invention can be prepared by chemically treating the surfaces of preformed toner particles to form higher melting protective skins resembling shells on the surfaces of the toner. More specifically, in one embodiment of the present invention there are provided developer compositions formulated by, for example, admixing low melting, about 220.degree. F. to about 300.degree. F., toner compositions following treatment with a halogen and carrier components. In one embodiment of the present invention there are provided toner compositions with low melting toner resins containing polymers prepared by bulk, solution, free radical, anionic, suspension, dispersion, or emulsion techniques, such as (A--B).sub.n wherein n represents the number of repeating polymer segments and where A and B represent monomeric or oligomeric segments of, for example, styrene and butadiene, respectively, which components possess in an embodiment of the present invention a desirable low fusion and low fusing energy; are easily jettable or processable into toner compositions; enable low temperature fusing; are optically clear; allow matte and gloss finishes; and with the toner resins illustrated herein there can in embodiments be fabricated brittle, rubbery, or other similar toner polymers with an optimized melt viscosity profile, and a lowering of the fusing temperature characteristics of the toner resin can be achieved. The toner polymers of the present invention can be processable by conventional toner means, that is these materials are extrudable, melt mixable and jettable. In another embodiment of the present invention toner particles generated by known in situ particle formation methods, such as dispersion polymerization with colorant, can be treated with a halogen, especially chlorine, to form encapsulated toners with nonblocking and low melting characteristics. Nonblocking ultra low melt toners of the present invention in embodiments can be prepared by the surface treatment thereof with halogen to form a protective halopolymer shell. The surface treatment method in an embodiment can be selected for toner particles comprised of unsaturated polymers that form covalent reaction products with halogens. The resulting toner materials in an embodiment of the present invention possess excellent triboelectric charging characteristics and also can fuse and fix to paper at about 50.degree. to 100.degree. F. lower than conventional known toners with polymers such as styrene methacrylates. Toner compositions formulated with the aforementioned ultra low melt toner resins have a number of advantages as illustrated herein. Thus, for example, the toner compositions in an embodiment of the present invention possess lower fusing temperatures, and therefore lower fusing energies are required for fixing, thus enabling less power consumption during fusing, and permitting extended lifetimes for the fuser systems selected. Moreover, high gloss images may be obtained at lower fuser set temperatures. The toners of the present invention can be fused (fuser roll set temperature) at temperatures of between 220.degree. and 320.degree. F. in embodiments of the present invention as compared to a number of currently commercially available toners which fuse at temperatures of from about 300.degree. to about 370.degree. F. With further respect to the present invention, the ultra low melt resins have, for example, in embodiments thereof a glass transition temperature of from about 24.degree. to about 72.degree. C. and in embodiments employing cryogenic jetting conditions, glass transition temperatures of from about 0.degree. or less to about 24.degree. C. Known nonblocking characteristics, that is noncaking or retaining substantially all the properties of a free flowing powder at temperatures of, for example, about 120.degree. F. or less are obtained with the toner compositions of the present invention in embodiments thereof. In an embodiment, the encapsulated ultra low melt resin particles of the present invention have a number average molecular weight of from about 3,000 to about 100,000 and preferably from about 6,000 to about 50,000. Also, the economical toner and developer (toner+carrier) compositions of the present invention are particularly useful in electrophotographic imaging and printing systems, including color, especially xerographic imaging processes that are designed for the generation of full color images. Both matte and gloss images may be achieved according to the resin fusing conditions selected. Further, the treated toner compositions of the present invention can be selected for single component development in that, for example, the toners resist smearing, and do not form toner aggregates under the pressure stresses usually selected for such development systems.
The electrostatographic process, and particularly the xerographic process, is well known. This process involves the formation of an electrostatic latent image on a photoreceptor, followed by development, and subsequent transfer of the image to a suitable substrate. Numerous different types of xerographic imaging processes are known wherein, for example, insulative developer particles or conductive toner compositions are selected depending on the development systems used. Of known value with respect to the aforementioned developer compositions, for example, is the appropriate triboelectric charging values associated therewith as it is these values that can enable continued constant developed images of high quality and excellent resolution and admixing characteristics. Specifically, thus toner and developer compositions are known, wherein there are selected as the toner resin styrene acrylates, styrene methacrylates, and certain styrene butadienes including those available as PLIOTONES.RTM.. Other resins have also been selected for incorporation into toner compositions inclusive of the polyesters as illustrated in U.S. Pat. No. 3,590,000. Moreover, it is known that single component magnetic toners can be formulated with styrene butadiene resins, particularly those resins available as PLIOLITE.RTM.. In addition, positively charged toner compositions containing various resins, inclusive of certain styrene butadienes and charge enhancing additives, are known. For example, there are described in U.S. Pat. No. 4,560,635, the disclosure of which is totally incorporated herein by reference, positively charged toner compositions with distearyl dimethyl ammonium methyl sulfate charge enhancing additives. The '635 patent also illustrates the utilization of suspension polymerized styrene butadienes for incorporation into toner compositions, reference for example working Example IX.
In a patentability search report, the following two United States patents were listed:
U.S. Pat. No. 4,971,880; Patentee: Hotomi et al.; Issued: Nov. 20, 1990.
U.S. Pat. No. 4,902,597; Patentee: Takeda et al.; Issued: Feb. 20, 1990.
U.S. Pat. No. 4,971,880 to Hotomi et al., assigned to Minolta, discloses a developer containing halogenated carbon particles prepared by plasma polymerization. A binder resin may comprise a styrene butadiene copolymer.
U.S. Pat. No. 4,902,597 to Takeda et al., assigned to Fuji Xerox, discloses a developer comprising a binder resin such as a styrene butadiene copolymer into which a fluorine-containing resin such as tetrafluoroethylene is incorporated.
Numerous patents are in existence that illustrate toner compositions with various types of toner resins including, for example, U.S. Pat. Nos. 4,104,066, polycaprolactones; 3,547,822, polyesters; 4,049,447, polyesters; 4,007,293, polyvinyl pyridine-polyurethane; 3,967,962, polyhexamethylene sebaccate; 4,314,931, polymethyl methacrylates; U.S. Pat. No. Re. 25,136, polystyrenes; and U.S. Pat. No. 4,469,770, styrene butadienes.
In U.S. Pat. No. 4,529,680, there are disclosed magnetic toners for pressure fixation containing methyl-1-pentene as the main component. More specifically, there are illustrated in this patent, reference column 2, beginning at line 66, magnetic toners with polymers containing essentially methyl-1-pentene as the main component, which polymer may be a homopolymer or copolymer with other alpha-olefin components. It is also indicated in column 3, beginning at around line 14, that the intrinsic viscosity of the polymer is of a specific range, and further that the melting point of the polymer is in a range of 150.degree. to 240.degree. C., and preferably 180.degree. to 230.degree. C. Other patents that may be of background interest include U.S. Pat. Nos. 3,720,617; 3,752,666; 3,788,994; 3,983,045; 4,051,077; 4,108,653; 4,258,116 and 4,558,108.
In addition, several patents illustrate toner resins including vinyl polymers, diolefins, and the like, reference for example U.S. Pat. No. 4,560,635. Moreover, there are illustrated in U.S. Pat. No. 4,469,770 toner and developer compositions wherein there are incorporated into the toner styrene butadiene resins prepared by emulsion polymerization processes.
Furthermore, a number of different carrier particles have been illustrated in the prior art, reference for example the U.S. Pat. No. 3,590,000 mentioned herein; and U.S. Pat. No. 4,233,387, the disclosures of which are totally incorporated herein by reference, wherein coated carrier components for developer mixtures, which are comprised of finely divided toner particles clinging to the surface of the carrier particles, are recited. Specifically, there are disclosed coated carrier particles obtained by mixing carrier core particles of an average diameter of from between about 30 microns to about 1,000 microns with from about 0.05 percent to about 3.0 percent by weight based on the weight of the coated carrier particles of thermoplastic resin particles. More specifically, there are illustrated in the '387 patent processes for the preparation of carrier particles by a powder coating process, and wherein the carrier particles consist of a core with a coating thereover comprised of polymers. The carrier particles selected can be prepared by mixing low density porous magnetic, or magnetically attractable metal core carrier particles with from, for example, between about 0.05 percent and about 3 percent by weight based on the weight of the coated carrier particles of a polymer until adherence thereof to the carrier core by mechanical impaction or electrostatic attraction; heating the mixture of carrier core particles and polymer to a temperature, for example, of between from about 200.degree. F. to about 550.degree. F. for a period of from about 10 minutes to about 60 minutes enabling the polymer to melt and fuse to the carrier core particles; cooling the coated carrier particles; and thereafter classifying the obtained carrier particles to a desired particle size. In U.S. Pat. Nos. 4,937,166 , and 4,935,326, the disclosures of which are totally incorporated herein by reference, there are illustrated, for example, carrier particles comprised of a core with a coating thereover comprised of a mixture of a first dry polymer component and a second dry polymer component not in close proximity to the first polymer in the triboelectric series. Therefore, the aforementioned carrier compositions can be comprised of known core materials including iron with a dry polymer coating mixture thereover. Subsequently, developer compositions can be generated by admixing the aforementioned carrier particles with a toner composition comprised of resin particles and pigment particles. Other patents include U.S. Pat. No. 3,939,086, which teaches steel carrier beads with polyethylene coatings, see column 6; U.S. Pat. Nos. 3,533,835; 3,658,500; 3,798,167; 3,918,968; 3,922,382; 4,238,558; 4,310,611; 4,397,935 and 4,434,220.
In copending application U.S. Ser. No. 751,922, now abandoned, entitled Developer Compositions With Specific Carrier Particle Developers, the disclosure of which is totally incorporated herein by reference, there are illustrated toners with styrene butadiene copolymers, pigment particles inclusive of magnetites, charge control additives, and carrier particles containing a core with a coating thereover of vinyl copolymers, or homopolymers, such as vinyl chloride/vinyl acetate.
Semicrystalline polyolefin resins or blends thereof are illustrated in U.S. Pat. Nos. 4,990,424 and 4,952,477, the disclosures of which are totally incorporated herein by reference. More specifically, in U.S. Pat. No. 4,952,477 there are disclosed toners with semicrystalline polyolefin polymer or polymers with a melting point of from about 50.degree. to about 100.degree. C., and preferably from about 60.degree. to about 80.degree. C. with the following formulas wherein x is a number of from about 250 to about 21,000; the number average molecular weight is from about 17,500 to about 1,500,000 as determined by GPC; and the M.sub.w /M.sub.n dispersity ratio is from about 2 to about 15.
I. Polypentenes--(C.sub.5 H.sub.10).sub.x PA0 II. Polytetradecenes--(C.sub.14 H.sub.28).sub.x PA0 III. Polypentadecenes--(C.sub.15 H.sub.30).sub.x PA0 IV. Polyhexadecenes--(C.sub.16 H.sub.32).sub.x PA0 V. Polyheptadecenes--(C.sub.17 H.sub.34).sub.x PA0 VI. Polyoctadecenes--(C.sub.18 H.sub.36).sub.x PA0 VII. Polynonadecenes--(C.sub.19 H.sub.38).sub.x ; and PA0 VIII. Polyeicosenes--(C.sub.20 H.sub.40).sub.x.
Examples of specific semicrystalline polyolefin polymers illustrated in this copending application include poly-1-pentene; poly-1-tetradecene; poly-1-pentadecene; poly-1-hexadecene; poly-1-heptadecene; poly-1-octadene; poly-1-nonadecene; poly-1-eicosene; mixtures thereof; and the like. These materials are particularly suitable for making matte or low gloss black copies and prints.
Although the above described toner compositions and resins are suitable for their intended purposes, especially those of U.S. Pat. Nos. 4,952,477 and 4,990,424 now U.S. Pat. No. 4,790,424 in most instances, there continues to be a need for toner and developer compositions containing new resins. More specifically, there is a need for toners which can be fused at lower energies than many of the presently available selected toners but which retain many or all of the same desirable physical properties, for example, hardness, processibility, clarity, high gloss durability, and the like. There is also a need for resins that can be selected for toner compositions which are low cost, nontoxic, nonblocking at temperatures of less than 50.degree. C., jettable, melt fusible with a broad fusing latitude, cohesive above the melting temperature, and triboelectrically chargeable. In addition, there remains a need for toner compositions, especially low melt toners, which can be fused at low temperatures, that is for example 260.degree. F. or less, as compared to a number of toners presently in commercial use, which require fusing temperatures of about 300.degree. to 325.degree. F., thereby enabling with the compositions of the present invention the utilization of lower fusing temperatures, and lower fusing energies permitting less power consumption during fusing, and allowing the fuser system, particularly the fuser roll selected, to possess extended lifetimes. There is also a need for toners which provide high gloss for pictorial color image quality. Another need resides in the provision of developer compositions comprised of the toner compositions illustrated herein, and carrier particles. Moreover, there is a need for low melting toner compositions which do not smear, or wherein smearing is minimized, and agglomeration is substantially avoided in single and two component development systems, especially single component development housings. There also remains a need for toner and developer compositions containing additives therein, for example charge enhancing components, thereby providing positively or negatively charged toner compositions. There is also a need for low melting toners which do not agglomerate, cake or block especially under ambient atmosphere and machine operating conditions. There is also a need for colored toners with passivated surfaces to assist in controlling the triboelectric properties thereof. Furthermore, there is a need for toner and developer compositions with ultra low melt resin polymers that will enable the generation of solid image areas with substantially no background deposits, and full gray scale production of half tone images in electrophotographic imaging and printing systems.
There is also a need for ultra low melt resin nonblocking toners with glass transition temperatures of, for example, from about 24.degree. to about 110.degree. C., and preferably from about 33.degree. to about 60.degree. C.; and wherein the toner compositions can be formulated into stable developer compositions which are useful in single and two component electrophotographic imaging and printing systems, and wherein fusing can, for example, be accomplished by flash, radiant, with heated ovens, cold pressure, and heated roller fixing methods in embodiments of the present invention.
There is also a need for toners with low glass transition temperature cores with glass transition temperatures of, for example, from about 24.degree. to about 110.degree. C. and preferably from about 33.degree. to about 60.degree. C. encapsulated with higher glass transition temperature polymer shells. Shell polymer glass transition temperatures may range from about 24.degree. to about 110.degree. C. and preferably these temperatures are greater than 55.degree. C.